Method of gem cutting



Oct. 12, 1965 c. R. DROWN 3,211,141

METHOD OF GEM CUTTING Filed Feb. 13, 1963 INVENTOR 4 5/00 A TTORNE YS United States Patent 3,211,141 METHOD OF GEM CUTTING Claude R. Drown, Tip Top Bldg, 351 E. 42nd St, Casper, Wyo. Filed Feb. 13, 963, Ser. No. 258,313 2 Claims. (Cl. 125-30) This invention relates to improvements in a new and novel method of gem cutting, and more particularly to the severance of an accurately outlined gem piece from a blank of gem material, the invention being highly desirable for use by both professional and hobbyist lapidarists, as will be apparent to those skilled in the art.

In the cutting of individual gems from the raw material, a block of gem material is first sliced into blanks, which may vary in thickness depending upon the size and shape of gem desired. The blanks themselves are most frequently irregular in shape, and are of such size that several resultant gems may be cut from the same blank. This requires some trial and error in order to determine the size, shapes, and positioning of the gems to be cut from the blank so that as little as possible of the rough or raw gem material is wasted.

In the past, marking out the outlines of individual gems in a blank of gem material for ultimate cutting has been done by the use of templets containing various shapes and sizes of apertures defining ultimate gem outlines. A templet is placed over a blank of gem material, and a gem is outlined by marking the blank with an aluminum pencil, following the contour of an aperture in the templet. This method of procedure, however, was subject to many disadvantages and objections.

For example, with the former procedure, it was difficult to maintain a sharp point on an aluminum pencil because that pencil must be comparatively soft in order to show a readable mark on the blank. For that reason it is extremely diflicult, if not actually impossible to mark a perfect sized shape or form on the blank even though the templet may have a perfectly shaped aperture therein, because the sharpness of the point on the aluminum pencil will vary materially even in one marking. After some usage, the templet itself becomes slightly enlarged through abrasion by the marking pencil and therefore less accurate. Thus, with this formerly known method it was objectionably difiicult in marking accurate sizes and shapes for the ultimate gems. Also, because of the necessary shape of the templet, the balance of the blank is hidden or occluded by the templet while marking out an individual gem shape, and therefore it was objectionably difficult to make a layout of markings on a blank of gem material in a manner such as to conserve as much of the material as possible. Further, with the use of aluminum pencil markings, any mistakes in making layout had to be buffed out before remarking. In addition it may be mentioned that Water or oil or other materials used while working or cutting the blank often makes aluminum pencil marks extremely ditficult to follow.

With the foregoing in mind, it is an important object of the instant invention to provide a method of gem cutting wherein the shape of the gems may be more accurately laid out, in a simpler and more facile manner with less trial and error procedure than was necessitated heretofore.

It is also an object of this invention to utilize masking patches of pressure sensitive adhesive tape in various shapes and sizes to outline the resultant gems on a blank of gem material, whereby each patch is exactly the correct size every time.

Still another feature of this invention is the provision of a method of gem cutting in which the means utilized to outline a resultant gem on a blank of gem material 3,211,141 Patented Oct. 12, 1965 may be readily removed and repositioned to better arrange a layout of several gem outlines for conservation of material, and no bufling or other operations are necessary to remove previous markings.

Still another object of this invention is the provision of a method of gem cutting resulting in optimum conservation of material because the remainder of the blank is visible at all times when a resultant gem is outlined thereon.

Still another desideratum of this invention is the provision of a method of gem cutting with the use of gem outlining means on a blank of gem material that are far easier to see while sawing, grinding and performing similar operations than is an aluminum pencil line, with the result that greater accuracy is obtained in the cutting of the actual gem.

It is also an object of the invention to provide means for outlining gems upon a block of gem material that will not be displayed or adversely effected by water or other solutions utilized when the blank is sawed, ground, or otherwise cut.

While some of the more salient features, characteristics and advantages of the instant invention have been above pointed out, others will become apparent from the following disclosures, taken in conjunction with the accompanying drawing, in which:

FIGURE 1 is a fragmentary plan view of a series of unused masking patches mounted upon removable facing strips;

FIGURE 2 is a view similar to FIGURE 1, but showing masking patches of different outlines;

FIGURE 3 is a greatly enlarged fragmentary vertical sectional view through the assembly of FIGURE 2 taken substantially as indicated by the line III-III of FIG- URE 2, looking in the direction of the arrows;

FIGURE 4 is a plan view of a blank of gem material showing a partial layout of masking patches thereon arranged so as to acquire desired shapes and yet conserve material;

FIGURE 5 is a fragmentary plan view of a portion of the structure of FIGURE 4 illustrating how the resultant gem is cut from the blank portion;

FIGURE 6 is a view similar in character to FIGURE 5, but showing the cutting of a gem of different shape; and

FIGURE 7 is a greatly enlarged fragmentary transverse sectional view taken substantially as indicated by the line VII-VII of FIGURE 6.

As shown on the drawings:

While the instant invention is highly desirable for the cutting of non-faceted gem stones, such as cabochons, it will be apparent that it might also be utilized for rough cutting faceted gem stones prior to the application of the facets themselves. For purposes of illustration, however, the method is herein shown and described in connection with the cutting of the cabochon-type gem stone.

Since the instant invention is applicable to precious, semi-precious, synthetic and other stones or minerals that may be of little value, the terms gem and gem material are herein used in the broadest sense, rather than their technical meanings, to include any organic or inorganic substance regardless of value which may be cut to provide an ornamental stone of sutficient beauty and durability for use as personal adornment in articles of jewelry and related objects.

In the illustrated embodiment of this invention, the material utilized to mark out the shape of gem stones is shown in FIGURES l and 2. In FIGURE 1 round adhesive patches 1 are shown mounted upon a facing sheet generally indicated by numeral 2 which is of release material or is provided with a release surface on which the adhesive face of the patches rest. This facing strip is preferably severed as indiacted at 3 and 4 longitudinally thereof, so that there are in fact three separate facing strips used. Each patch is preferably mounted centrally or evenly over one of the slits 3 or 4 in the facing sheet, and this arrangement renders the patches extremely easy to remove from the facing sheet at the time they are put to use, without any distortion or bending of the patches.

In FIGURE 2 marquise or navette shaped patches 5 are shown mounted upon the same type of facing means as above described. Obviously, numerous shapes of the patches could be provided on one facing assembly if so desired, but in commercial manufacture it is more economical to provide strips or sheets containing a predetermined number of identical patches.

With reference to FIGURE 3 it will be seen that each patch comprises a backing 6 with a pressure sensitive adhesive spread 7 on the undersurface of the backing. The backing may be of any suitable material, transparent if so desired, but is preferably of material that will be unaffected by water, oils, or other liquids utilized in the process of gem cutting. Numerous types of satisfactory backing materials are on the market including various plastics or fabrics treated with material to render them liquid impervious, such as a pyroxlin coating. Treated or coated paper backings are also satisfactory, the particular material involved not being an essential part of the invention as long as the patches resist cutting fluids.

In FIGURE 4 there is shown a blank 8 sliced from a block of stone or gem material. As illustrated, the slice will be of an irregular shape in nearly every instance. On one face of the blank the gem defining patches may be secured by their adhesive surfaces. The disposition of the patches upon the blank depends first upon the desired shapes of gems to be cut from the blank, and secondly upon conserving as much as possible of the rough blank. Accordingly, by way of example and not by way of limitation, I have illustrated a partial arrangement of patches upon the blank 8. The patches include three round patches 1, above described, one of the marquise patches 5, a heart-shaped patch 9, a square-shaped patch 10, and a pear-shaped patch 11. These patches are so disposed as to define a small space sufficient for a saw out between adjacent patches and relatively positioned to insure as little as possible wastage of the blank material.

It will be noted that it is easy to position the patches upon the blank with a minimum of trial and error, because while one patch is being placed in position the remainder of the blank surface is plainly visible. Should a pat-ch unintentionally be wrongly located, it is a simple expedient to remove it and replace it, no buffing or other operation upon the blank being necessary. It is also apparent from the showing in this figure that each proposed gem is perfectly and sharply defined by the corresponding patch, and oil, water, or other liquids used during the cutting process will not disturb the sharp definition presented by each patch.

In cutting a gem defined by each patch, a strip may be removed from the blank 8 by sawing along straight lines 12 and 13 with a diamond saw. Thereafter, transverse cuts may be made in the removed strip between adjacent patches to single out one patch and some of the blank there beneath as seen in FIGURES 5 and 6. As shown by the various straight lines 14 in FIGURE 5, the blank material is cut away as closely as possible by sawing to the circumference of the patch 1. This procedure continues until there is left only a plurality of triangular portions 15 projecting from the blank material beyond the patch. These portions may then be ground off so that the blank stock is ultimately reduced to the very edge of the patch. The resultant gem piece is accurate in shape and has been cut to that shape more facilely and more simply than was heretofore possible. The guiding patch may then be removed and the gem piece further ground and polished to the extent desired.

In FiGURE 6 I have illustrated how the pear-shaped gem piece under the guiding patch 11 may similarly be cut, first by sawing along straight lines 16 until there remains only slight projecting portions 17, and these are then ground off to the very edge of the pear-shaped patch.

Regardless of the shape of the patch, the instant invention facilitates the cutting and shaping of the gem piece, and the entire procedure is simple, accurate, rapid, and economical to practice.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

I claim as my invention:

1. A method of gem cutting to provide a generally curved outline including the steps of:

providing a blank of gem material,

securing gem-defining patches on said blank in an arrangement to conserve the blank material,

sawing off a portion of said blank carrying a patch,

sawing said portion in straight line cuts tangential to the bounding edges of the patch, and leaving irregular substantially triangular portions of said portion of the blank outside the boundary edges of the patch,

grinding off the remainder of said portion to the bounding edge of the patch,

removing the patch, and

finishing the gem defined by said patch.

2. A method of gem cutting to provide a generally curved outline including the steps off:

providing a blank of gem material larger than a predetermined outline,

securing a gem-defining patch having the desired outline on said blank, sawing said blank in straight line cuts tangential to the bounding edge of the patch and leaving irregular substantially triangular portions of the blank outside the boundary edge of the patch, grinding off said portions to the bounding edge of the patch, removing the patch, and finishing the gem which was defined by said patch.

References Cited by the Examiner UNITED STATES PATENTS 671,831 4/01 Loesser -30 694,215 2/02 Stuurman 125-30 1,843,432 2/32 Nickerson 29-425 X 2,190,582 2/40 Wolf 33-174 2,267,336 12/41 Kindelberger 33-174 2,395,215 2/46 Cochrane 33-174 2,596,179 5/52 Seymour 156-267 X 2,804,108 8/57 Boylan 41-10 2,969,106 1/61 Reibel et al 154-535 2,975,091 3/61 Tobey 154-535 3,077,797 2/63 Payne 76-107 ROBERT C. RIORDON, Primary Examiner.

JOHN C. CHRISTIE, HAROLD D. WHITEHEAD,

LESTER M, SWINGLE, Examiners, 

1. A METHOD OF GEM CUTTING TO PROVIDE A GENERALLY CURVED OUTLINE INCLUDING THE STEPS OF: PROVIDING A BLANK OF GEM MATERIAL, SECURING GEM-DEFINING PATCHES ON SAID BLANK IN AN ARRANGEMENT TO CONSERVE THE BLANK MATERIAL SAWING OFF A PORTION OF SAID BLANK CARRYING A PATCH, SAWING SAID PORTION IN STRAIGHT LINE CUTS TANGENTIAL TO THE BOUNDING EDGES OF THE PATCH, AND LEAVING IRREGUALR SUBSTANTIALLY TRIANGULAR PORTIONS OF SAID PORTION OF THE BLANK OUTSIDE THE BOUNDARY EDGES OF THE PATCH, GRINDING OFF THE REMAINDER OF SAID PORTION TO THE BOUNDING EDGE OF THE PATCH, REMOVING THE PATCH, AND FINISHING THE GEM DEFINED BY SAID PATCH. 